The use of intravascular catheters is an effective method for treating many types of vascular disease. In general, an intravascular catheter is inserted into the vascular system of a patient and navigated through the vasculature to a desired target site. Using this method, virtually any target site in the patient's vascular system may be accessed, including the coronary, cerebral, and peripheral vasculature. Example therapeutic applications of intravascular catheters include percutaneous transluminal angioplasty (PTA), and percutaneous transluminal coronary angioplasty (PTCA).
Intravascular catheters are commonly used in conjunction with a guidewire. A guidewire may be advanced through the patient's vasculature until it reaches a target location. Once in place, the catheter may be threaded onto the guidewire and urged distally until the distal end of the catheter reaches the target location.
Typically, the guidewire is inserted into the patient's vasculature from a convenient percutaneous location and then advanced to a target region. The path traversed by the catheter through the vascular system is often tortuous, requiring the guidewire to change direction frequently. To conform to a patient's circuitous vascular system, the guidewire is preferably flexible, particularly near the distal end.
During its course through the vasculature, the guidewire may confront a stenosis, lesion, or clot. Sometimes, the stenosis completely blocks the vessel, as is the case with a chronic total occlusion (CTO). In these cases, the guidewire may not be able to penetrate the occlusion, owing to its flexibility. To overcome this difficulty, a catheter can be inserted over the guidewire to increase rigidity, or a more rigid guidewire may replace the existing guidewire.
If the occlusion is hard plaque, even the catheter and guidewire combination may not be able to cross it. In these cases, the intravascular catheter may be replaced by a crossing catheter. A crossing catheter may be configured to advance through the occlusion. For example, the crossing catheter may include a vibrating distal portion, a smaller profile than the intravascular catheter, a rigid distal portion, and/or a tapered distal tip enabling it to penetrate through hard plaques relatively easily. Once the plaque is crossed, the crossing catheter is removed and replaced by a balloon catheter to enlarge the pathway through the occlusion and/or positions a stent across the occlusion.
In this described arrangement, once the occlusion is crossed, the crossing catheter is retracted, and the balloon catheter is inserted in its place. Retraction and replacement, however, increases operation time and cost. Moreover, sometimes, the pathway formed through the plaque may not be sufficient to insert the flexible balloon catheter, increasing placement complexity.
Therefore, there exists a need for an integrated medical device that can penetrate the occlusion and without complete retraction provide interventional treatment (for example, but not limited to, dilating the occlusion or placing a stent) at the target location.